Abstract
In 1996 the CCT initiated five key comparisons of realisations of the ITS-90 in various parts of the range. CCT-K1 concerns the range 0.65 K to 24.5561 K, where the ITS-90 is defined by specified vapour-pressure equations for 3He (0.65 K to 3.2 K) and 4He (1.25 K to 5.0 K) and by interpolation equations for a constant-volume gas thermometer (3 K to 24.5561 K). The transfer standards were rhodium–iron resistance thermometers calibrated by the seven participating laboratories. The report describes the comparison experiments, the results and uncertainties, and the calculation of interlaboratory equivalences. The comparison has been concluded by preparing an entry for Appendix B of the BIPM Key Comparison Database.
Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.
The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).